[PATCH 0/5] PM / devfreq: Convert to platform remove callback returning void

[PATCH 0/5] PM / devfreq: Convert to platform remove callback returning void

[Uwe Kleine-König]

Hello,

this series converts all drivers below drivers/devfreq to struct
platform_driver::remove_new(). See commit 5c5a7680e67b ("platform: Provide a
remove callback that returns no value") for an extended explanation and the
eventual goal.

All conversations are trivial, because their .remove() callbacks
returned zero unconditionally.

There are no interdependencies between these patches, so they could be
picked up individually. But I'd hope that they get picked up all
together by the devfreq maintainers.

Best regards
Uwe

Uwe Kleine-König (5):
  PM / devfreq: exynos-nocp: Convert to platform remove callback returning void
  PM / devfreq: exynos-ppmu: Convert to platform remove callback returning void
  PM / devfreq: mtk-cci: Convert to platform remove callback returning void
  PM / devfreq: rk3399_dmc: Convert to platform remove callback returning void
  PM / devfreq: sun8i-a33-mbus: Convert to platform remove callback returning void

 drivers/devfreq/event/exynos-nocp.c | 6 ++----
 drivers/devfreq/event/exynos-ppmu.c | 6 ++----
 drivers/devfreq/mtk-cci-devfreq.c   | 6 ++----
 drivers/devfreq/rk3399_dmc.c        | 6 ++----
 drivers/devfreq/sun8i-a33-mbus.c    | 6 ++----
 5 files changed, 10 insertions(+), 20 deletions(-)

base-commit: 67908bf6954b7635d33760ff6dfc189fc26ccc89
-- 
2.43.0

[PATCH 5/5] PM / devfreq: sun8i-a33-mbus: Convert to platform remove callback returning void

[Uwe Kleine-König]

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/devfreq/sun8i-a33-mbus.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/devfreq/sun8i-a33-mbus.c b/drivers/devfreq/sun8i-a33-mbus.c
index 13d32213139f..bcf654f4ff96 100644
--- a/drivers/devfreq/sun8i-a33-mbus.c
+++ b/drivers/devfreq/sun8i-a33-mbus.c
@@ -458,7 +458,7 @@ static int sun8i_a33_mbus_probe(struct platform_device *pdev)
 	return dev_err_probe(dev, ret, err);
 }
 
-static int sun8i_a33_mbus_remove(struct platform_device *pdev)
+static void sun8i_a33_mbus_remove(struct platform_device *pdev)
 {
 	struct sun8i_a33_mbus *priv = platform_get_drvdata(pdev);
 	unsigned long initial_freq = priv->profile.initial_freq;
@@ -475,8 +475,6 @@ static int sun8i_a33_mbus_remove(struct platform_device *pdev)
 	clk_rate_exclusive_put(priv->clk_mbus);
 	clk_rate_exclusive_put(priv->clk_dram);
 	clk_disable_unprepare(priv->clk_bus);
-
-	return 0;
 }
 
 static const struct sun8i_a33_mbus_variant sun50i_a64_mbus = {
@@ -497,7 +495,7 @@ static SIMPLE_DEV_PM_OPS(sun8i_a33_mbus_pm_ops,
 
 static struct platform_driver sun8i_a33_mbus_driver = {
 	.probe	= sun8i_a33_mbus_probe,
-	.remove	= sun8i_a33_mbus_remove,
+	.remove_new = sun8i_a33_mbus_remove,
 	.driver	= {
 		.name		= "sun8i-a33-mbus",
 		.of_match_table	= sun8i_a33_mbus_of_match,
-- 
2.43.0

Re: [PATCH 5/5] PM / devfreq: sun8i-a33-mbus: Convert to platform remove callback returning void

[Jernej Škrabec]

Dne ponedeljek, 04. marec 2024 ob 22:28:43 CET je Uwe Kleine-König napisal(a):
> The .remove() callback for a platform driver returns an int which makes
> many driver authors wrongly assume it's possible to do error handling by
> returning an error code. However the value returned is ignored (apart
> from emitting a warning) and this typically results in resource leaks.
> 
> To improve here there is a quest to make the remove callback return
> void. In the first step of this quest all drivers are converted to
> .remove_new(), which already returns void. Eventually after all drivers
> are converted, .remove_new() will be renamed to .remove().
> 
> Trivially convert this driver from always returning zero in the remove
> callback to the void returning variant.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>

Best regards,
Jernej

> ---
>  drivers/devfreq/sun8i-a33-mbus.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/devfreq/sun8i-a33-mbus.c b/drivers/devfreq/sun8i-a33-mbus.c
> index 13d32213139f..bcf654f4ff96 100644
> --- a/drivers/devfreq/sun8i-a33-mbus.c
> +++ b/drivers/devfreq/sun8i-a33-mbus.c
> @@ -458,7 +458,7 @@ static int sun8i_a33_mbus_probe(struct platform_device *pdev)
>  	return dev_err_probe(dev, ret, err);
>  }
>  
> -static int sun8i_a33_mbus_remove(struct platform_device *pdev)
> +static void sun8i_a33_mbus_remove(struct platform_device *pdev)
>  {
>  	struct sun8i_a33_mbus *priv = platform_get_drvdata(pdev);
>  	unsigned long initial_freq = priv->profile.initial_freq;
> @@ -475,8 +475,6 @@ static int sun8i_a33_mbus_remove(struct platform_device *pdev)
>  	clk_rate_exclusive_put(priv->clk_mbus);
>  	clk_rate_exclusive_put(priv->clk_dram);
>  	clk_disable_unprepare(priv->clk_bus);
> -
> -	return 0;
>  }
>  
>  static const struct sun8i_a33_mbus_variant sun50i_a64_mbus = {
> @@ -497,7 +495,7 @@ static SIMPLE_DEV_PM_OPS(sun8i_a33_mbus_pm_ops,
>  
>  static struct platform_driver sun8i_a33_mbus_driver = {
>  	.probe	= sun8i_a33_mbus_probe,
> -	.remove	= sun8i_a33_mbus_remove,
> +	.remove_new = sun8i_a33_mbus_remove,
>  	.driver	= {
>  		.name		= "sun8i-a33-mbus",
>  		.of_match_table	= sun8i_a33_mbus_of_match,
> 

RE: [PATCH 0/5] PM / devfreq: Convert to platform remove callback returning void

[Chanwoo Choi]

> -----Original Message-----
> From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> Sent: Tuesday, March 5, 2024 6:29 AM
> To: Chanwoo Choi <cw00.choi@samsung.com>; MyungJoo Ham
> <myungjoo.ham@samsung.com>; Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>; Alim Akhtar
> <alim.akhtar@samsung.com>; linux-pm@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-samsung-soc@vger.kernel.org;
> kernel@pengutronix.de; Matthias Brugger <matthias.bgg@gmail.com>;
> AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>; linux-
> mediatek@lists.infradead.org; Chen-Yu Tsai <wens@csie.org>; Jernej Skrabec
> <jernej.skrabec@gmail.com>; Samuel Holland <samuel@sholland.org>; linux-
> sunxi@lists.linux.dev
> Subject: [PATCH 0/5] PM / devfreq: Convert to platform remove callback
> returning void
> 
> Hello,
> 
> this series converts all drivers below drivers/devfreq to struct
> platform_driver::remove_new(). See commit 5c5a7680e67b ("platform: Provide a
> remove callback that returns no value") for an extended explanation and the
> eventual goal.
> 
> All conversations are trivial, because their .remove() callbacks returned
> zero unconditionally.
> 
> There are no interdependencies between these patches, so they could be picked
> up individually. But I'd hope that they get picked up all together by the
> devfreq maintainers.
> 
> Best regards
> Uwe
> 
> Uwe Kleine-König (5):
>   PM / devfreq: exynos-nocp: Convert to platform remove callback returning
> void
>   PM / devfreq: exynos-ppmu: Convert to platform remove callback returning
> void
>   PM / devfreq: mtk-cci: Convert to platform remove callback returning void
>   PM / devfreq: rk3399_dmc: Convert to platform remove callback returning
> void
>   PM / devfreq: sun8i-a33-mbus: Convert to platform remove callback returning
> void
> 
>  drivers/devfreq/event/exynos-nocp.c | 6 ++----
> drivers/devfreq/event/exynos-ppmu.c | 6 ++----
>  drivers/devfreq/mtk-cci-devfreq.c   | 6 ++----
>  drivers/devfreq/rk3399_dmc.c        | 6 ++----
>  drivers/devfreq/sun8i-a33-mbus.c    | 6 ++----
>  5 files changed, 10 insertions(+), 20 deletions(-)
> 
> base-commit: 67908bf6954b7635d33760ff6dfc189fc26ccc89
> --
> 2.43.0
> 

Applied it. Thanks.

Best Regards,
Chanwoo Choi